Self-similar light-scattering spectra of β relaxation near the liquid-glass transition

We report a light-scattering observation of {β} relaxation in [Ca(NO₃{)}₂]0.4-(KNO₃{)}0.6in the vicinity of the liquid-glass transition. The spectra exhibit self-similarity with I(ω)=A/{{{ω}}}^{1{{-}}a}$ over a spectral range of nearly 3 orders of magnitude in both the liquid and glass phases. This result agrees with predictions of mode-coupling theories of the glass transition. However, the value of a is strongly temperature dependent, a result not predicted by the theory. The spectra are strongly depolarized with a depolarization ratio of {~}0.75.